Wheel tread and rim

Method for repair of rail wheels

The damage to the wheel tread of high-speed trains mainly originates from three aspects: circumferential wear, rolling contact fatigue, and braking. Circumferential wear will cause changes in the shape of the wheel tread, which will lead to mismatching of wheel-rail profiles and change the wheel-rail contact geometry; rolling contact fatigue damage will cause fatigue cracks and peel off pieces; braking will cause thermal peeling and heat Cracks, emergency braking may also cause tread scratches. These three types of damage do not exist independently when the vehicle is running but affect each other.

Through laser cladding technology, WILA obtained an iron-based cladding layer that is metallurgically bonded to the surface of ER8 steel. The composition of the cladding layer mainly includes matrix γ-Fe and hard carbide Cr7C3 and alloy elements such as Mn, Mo, Ni, etc. These compounds form a replacement solid solution with γ-Fe in the cladding layer, which greatly increases the strength of the cladding layer. The solidification structure of the cladding layer is divided into plane crystal area, columnar dendrite area, cellular crystal area, and equiaxed dendrite area from the inside to the outside. The formation of these crystal structures is determined by the temperature gradient/solidification rate (G/R).

The repaired wheel tread has no flaw detection, the microhardness of the cladding layer is 444HV, and the relative wear resistance is as high as 2.1, which fully meets customer requirements.